理工类相同项单选集试卷（二）119.doc

想预览更多内容，点击预览全文
点击预览本文档（全文）

申明敬告：

本站所有内容均由合作方或网友上传，本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺！文档内容仅供研究参考，付费前请自行鉴别。如您付费，意味着您自己完全接受本站规则且自行承担所有风险，本站不退款、不进行额外附加服务；如果您已付费下载过本站文档，您可以点击这里二次下载

文档介绍

试卷第 PAGE 1 页共 NUMPAGES 2 页

理工类相同项单选集试卷

姓名:_____________ 年级:____________ 学号:______________

题型

选择题

填空题

解答题

判断题

计算题

附加题

总分

得分

评卷人

得分 1、Black Holes Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers (天文学家)think that at the center of a black hole there is a single point in space with infinite (无限的)density (稠密). This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point. Anything that crosses the black hole is pulled in by its great gr

最近下载